Development of Genetic Resistance to Infection

David P. Clark

“What does not kill me makes me stronger.”

—Friedrich Nietzsche

On average, the healthier, faster zebras escape being eaten by the lion and survive to carry on the species. Disease, like large predators, preferentially carries off the young, the old, the weak and crippled, and the feeble-minded, together with those who have no friends, family, or allies to help them. Vulnerability is not merely a physical matter. Declining mental alertness may increase vulnerability to disease due to lack of appropriate behavior. From a Darwinian perspective, both predation and disease improve the species, often in a rather nonspecific manner, by selecting for healthy and vigorous individuals. In ...